The invention relates to cloned DNA sequences analogous to the genomic RNA of a virus known as Lymphadenopathy-Associated Virus II ("LAV-II"), a process for the preparation of these cloned DNA sequences, and their use as probes in diagnostic kits. In one embodiment, the invention relates to a cloned DNA sequence analogous to the entire genomic RNA of HIV-2 and its use as a probe. The invention also relates to polypeptides with amino acid sequences encoded by these cloned DNA sequences and the use of these polypeptides in diagnostic kits.
According to recently adopted nomenclature, as reported in Nature, May 1986, a substantially-identical group of retroviruses which has been identified as one causative agent of AIDS are now referred to as Human Immunodeficiency Viruses I (HIV-1). This previously-described group of retroviruses includes Lymphadenopathy-Associated Virus I (LAV-I), Human T-cell Lymphotropic Virus-III (HTLV-III), and AIDS-Related Virus (ARV).
Lymphadenopathy-Associated Virus II has been described in U.S. application Ser. No. 835,228, which was filed Mar. 3, 1986, and is specifically incorporated herein by reference. Because LAV-II is a second, distinct causative agent of AIDS, LAV-II properly is classifiable as a Human Immunodeficiency Virus II (HIV-2). Therefore, "LAV-II" as used hereinafter describes a particular genus of HIV-2 isolates.
While HIV-2 is related to HIV-1 by its morphology, its tropism and its in vitro cytopathic effect on CD4 (T4) positive cell lines and lymphocytes, HIV-2 differs from previously described human retroviruses known to be responsible for AIDS. Moreover, the proteins of HIV-1 and 2 have different sizes and their serological cross-reactivity is restricted mostly to the major core protein, as the envelope glycoproteins of HIV-2 are not immune precipitated by HIV-1-positive sera except in some cases where very faint cross-reactivity can be detected. Since a significant proportion of the HIV infected patients lack antibodies to the major core protein of their infecting virus, it is important to include antigens of both HIV-1 and HIV-2 in an effective serum test for the diagnosis of the infection by these viruses.
HIV-2 was first discovered in the course of serological research on patients native to Guinea-Bissau who exhibited clinical and immunological symptoms of AIDS and from whom sero-negative or weakly sero-positive reactions to tests using an HIV-1 lysate were obtained. Further clinical studies on these patients isolated viruses which were subsequently named "LAV-II."
One LAV-II isolate was deposited at the Collection Nationale des Cultures de Micro-Organismes (C.N.C.M.) at the Institut Pasteur in Paris, France on Dec. 19, 1985 under Accession No. I-502. A second LAV-II isolate was deposited at C.N.C.M. on Feb. 21, 1986 under Accession No. I-532. This second isolate has been subsequently referred to a LAV-II ROD. Several additional isolates have been obtained from West African patients, some of whom have AIDS, others with AIDS-related conditions and others with no AIDS symptoms. All of these viruses have been isolated on normal human lymphocyte cultures and some of them were thereafter propagated on lymphoid tumor cell lines such as CEM and MOLT.
Due to the sero-negative or weak sero-positive results obtained when using kits designed to identify HIV-1 infections in the diagnosis of these new patients with HIV-2 disease, it has been necessary to devise a new diagnostic kit capable of detecting HIV-2 infection, either by itself or in combination with an HIV-1 infection. The present inventors have, through the development of cloned DNA sequences analogous to at least a portion of the genomic RNA of LAV-II ROD viruses, created the materials necessary for the development of such kits.